Ghaeles e



(No Model.)

C. E. SGRIBNER.

CIRCUIT FOR MULTIPLE SWITCH BOARDS FOR TELEPHONE EXCHANGES.

No. 271,279'. Patented Jan.30,1883.

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UNTTED STATES PATENT OEEIcE.

CHARLES E. SCRIBNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE VESTERNELECTRIC COMPANY, OF SAME PLACE.

CIRCUIT FOR MULTIPLE SWITCH-BOARDS FOR TELEPHONE-EXCHANGES.

SPECIFICATION forming part of Letters Patent No. 271,279, dated January30, 1883.

Application filed August 4, 1882. (No model.)

To all whom it may concern Be it known that I, CHARLEs E. SGRIBNER, acitizen of the United States, residing at Chicago, in the county of Cookand State of Illinois, have invented a certain new and usefulImprovement in Circuits for Multiple Switch-- Boards, ot' which the'following is a full, clear, concise, and exact description, referencebeing had to the accompanying drawing, forming a. part ot' thisspecification.

My invention relates to circuits for multiple switch-boards of atelephone-exchange; and it consists in the combinations hereindescribed, whereby any given telephone-line maybe connected with itsbolt or switch upon either ot' 4the multiple boards.

Heretofore each telephone-line has been con-v nected normally with allthe multiple boards. Switch-board room was thus provided for as manyswitchlnen as might be necessary. Different systems have been devised toenable switchinen at one board to see what lines are inA use at otherboards, in order that confusion may be avoided. As thus used, it is,however, possible for a switchman at one board to interfere with linesconnected atanother board; In my system, as herein described, thetelephone-lines are not connected with either of the multiple boards,except while in use for conversation, and the possibility ot confusionis obviated from the interference or meddling of switchmen at other ofthe multiple boards,`

since two lines7 when connected together for conversation upon onemultiple board,areopen to all other of the' multiple boards ofthesystem.

In the drawing I have shown three telephone-lines, a, b, and c, enteringthe central ottce. The subscribers respectively connected with theselines are provided with any of the well-known subscribers outfits. Thenormal circuit ot' each line is through a switch and an annunciator toground. Thus the circuit ot line a passes through switch a andannunciator a2 to ground, and is not connected with either ot themultiple or duplicate switchboards A, B, and C. The multipleswitchboards A, B, and C are each provided with `connecting plates orbolts-one plate or bolt the bolts of a series belonging to any givenline are connected to points near the switch of the line of the series.Thus bolts d' d2 d are connected respectively to points e .92.63, nearswitch a, as shown. Suppose, now, that the subscriber of line b has senta call to the central office. The switch man at board D, seeing theannunciator bZl'alL-immediately moves the switch b into contact with thepoint thus connecting the line with boltg upon switchboard A, as shown.The switchman at the multiple board A tinds out, by means olfv histelephone outtit, what line is Wanted. He then informs the switchman atboard D, who thereupon connects the line of the subscriber wanted withthe bolt ot' the line uponI the proper multiple switch-board. Thus linec is shownconnected by switch c to point h, and thus to bolt k ot' 7cboard A. The operator at multiple board A, now having rung up thesubscriber of line c, connects the bolts g and k through clearingoutannunciator l, as shown, in the usual manner. At a signal from theclearing-out annunciator, the plugs are removed from bolts g k. Theswitchman at board D then. replaces the switches b c upon theirground-connections, as indicated by thedotted lines, and thus restoresthe normal circuits of the lines b c. Y

Having thus` described my invention, what I claim is- 1. Two, three, ormore multiple switchboards with bolts and connecting-lines-one bolt foreach line on each multiple board-in combination with telephone-lines,the said telephonelines being` normally disconnected from all the boardsan d switching apparatus, whereby any telephone-line may be connected toeither one ot' the bolts ot' its series upon either of the boards.

2. A series of telephone-lines each normally passing at the centraloffice throughwa switch and annunciator to ground, in combination with aseries ot' bolts on multiple switch-boardsone series for each line andone bolt of each series on each board-whereby any two lines, whenconnected upon either multiple board are disconnected from all othermultipleboards, substantially as set forth.

In witness whereof 1-hereunto subscribe my naine this 26th day of July,A. D. 1882.

CHARLES E. SCRIBNER.

Witnesses PAUL A. STALEY, ERNEST l?. WARNER.

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